Sleeve For Shielding Electrical Joint

ABSTRACT

A splice for use in high voltage electrical environment employing a combination of cold-shrink and interference fit in a single splice component allowing for the use of a shortened core at a first cold splice end and the absence of a cable adapter at the interference fit second end.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication Ser. No. 61/635,835 for “Sleeve for Shielding ElectricalJoint,” filed Apr. 19, 2012, which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention disclosed herein relates to the field of highvoltage power connectors utilized in power distribution systems. Moreparticularly, the present invention relates to separable electricalconnectors and improvements in the assembly of separable electricalconnectors including a method for the placement of a premoldedhigh-voltage connector or other removable or permanent electricalinsulating device over a high-voltage cable in a safer manner during theassembly and servicing of power distribution systems requiring detachingand reattaching connectors from electrical equipment.

SUMMARY OF THE INVENTION

In order to efficiently transport electricity, conductors are energizedat high voltage. Conductors, generally manufactured of conductive metal,are configured into a plurality of wires, commonly referred to in theart as cables. More specifically, in the case of an electric cablecarrying electricity from an electrical substation to the vicinity of anend user, the cables—designed to operate up to 35,000 volts understandard conditions—are referred to as distribution cables. In manyapplications, it is necessary to insulate (i.e., cover the conductorwith an electrically insulating material) cables with a partially orfully insulating material.

The primary purpose of splicing is simply to allow for cabling to besectionalized (i.e., breaking up the lengths of cable into easily pulledsections). In order to allow for uninterrupted service, faultprotection, and maintenance, cables must be spliced and joined. The needfor high-voltage cable splicing may also arise due to additional cableconnection requirements resulting from residential expansion andincreasing energy demands. The disconnectable joints, which can mate upto four cables at one junction, need to functionally mate the conductor,insulation, and insulation shield in a manner to allow for the connectedcables to operate as one continuous cable. Unlike the splicing oflow-voltage devices, which may be accomplished with the use of simpleconnectors with minimal insulation (frequently constructed of copper,aluminum and like components), high-voltage devices require spliceswhich must maintain proper voltage grading, electrical insulation, andwater tightness. To achieve these requirements, premolded high-voltagesplices may include the use of one, two, three, or more insulatedmembers. In addition, a tight fitting rubber member or sleeve may alsobe employed to cover the cable member connections. Due to the fact thatthe sleeve is generally manufactured of one diameter, cable adapters maybe employed to accommodate a broad range of cable diameters. Therefore,in combination, the insulated members, sleeves and cable adapters securethe spliced region, thereby providing for protection against waterseepage into the connection. In addition, this type of assembly allowsthe cable-to-cable splice to achieve the desired voltage and insulationdemands. Such a fitting requires a careful and often timely installationprocess, which involves the connection of opposing cable members to,and/or the placement of cable adapters over, the cable insulation. Cableadapters or cable members are then connected to one another, or to otherconnector components, to provide a successful splice. Specifically,installation involves the cables being bolted onto the central bus andthe sleeves being slid over the cable insulating and mating with thecentral bus' insulation. It is further known in the art to requireadditional components to be installed on-site for securing opposingcable adapters or cable members to one another. As a result, as thenumber of additional installation components increases, more assemblytime may be required in the field, which can alter the efficiency of thesplicing operation.

For a successful splice, the cable members must fit securely within thecorresponding splice components. The inside diameter of the splicecomponent is generally designed to be smaller than the outer diameter ofeach corresponding cable member (i.e., commonly referred to as the“interference fit.”) To insure a snug fit, lubricant may be appliedalong the outside of the cable members and/or the inside of the cableadapters to assist in the installation process as the cable adapters arepulled over the corresponding cable members.

Cable joints are designed to be disconnected and reconnected withoutdamaging the joint. Typically, such joints are designed such that thejoint conductor is manufactured of a solid metal “bus” with flat pads atthe terminals. The flat pad connector is mounted onto the cable in amanner designed to be mated to the flat pad of the joint to ensure aneffective electrical connection. To complete the joint, the bus iscovered with an electrical insulating material and the insulatingmaterial is covered with a partially or fully conductive shield. Oncethe connection is established, it is necessary to restore the continuityof the insulation and insulation shield by using an elastomericmulti-layer sleeve to bridge the cable insulation and shield to thejoint insulation and shield.

In order to restore the continuity at the joint while shielding thejoint from the elements common in power systems, shields, commonlyreferred to as sleeves, are designed to provide an interference fit andincorporate heat-shrink characteristics or cold-shrink characteristicsto ensure a snug and water-tight joint. For example, a multi-layeredsleeve can have an interference fit over the cable and the joint. Asmentioned, the inside diameters of the ends of the sleeve are smallerthan the outside dimensions of the cable insulation at a first end andsmaller than the joint insulation at the second end. The interferencefit allows for a continuous insulation covering and provides for aleak-proof submersible design between the cables at the joint. Whileinterference fit designs accomplish the desired objectives in the field,such designs require the addition of cable adapters for mating to cablesof various sizes. While the use of additional components is tolerated inthe field since cable adapters are necessary to complete a securesplice, it is not ideal in the field as high voltage components oftenreside in confined spaces underground and the installation provesdifficult. Specifically, it is cumbersome to force fit the sleeve overthe cable adapter and the joint without dislodging the location of theadapter, thereby compromising the splice. Furthermore, the use of cableadapters creates additional interferences which may result in additionalpoints of fault thereby jeopardizing the integrity of the splice.

Heat-shrink sleeves are manufactured of material which remains at anexpanded size and shape at common environment temperatures andconditions. When sufficient heat is applied, the sleeve “shrinks” toform a secure fit between cable insulation/shield to jointinsulation/shield. Once reduced to a shrunken state, the elasticity ofthe material utilized allows for the sleeve to remain at such state withminimal expansion through a wide range of environmental conditions.While this is a common method utilized in the art, several disadvantagesare experienced in the field during assembly. For example, the thicknessof elastomeric sleeves makes it difficult for a lineman to applyconsistent and uniform heat in the confined space common to jointassembly in a high voltage environment. Such difficulty in the fieldoften results in scorching and deformation of the sleeve, rendering thesleeve ineffective in providing a water-resistant secure splice.Furthermore, since consistent and high temperature heat is required, asafety concern is apparent.

In the case of the cold-shrink sleeves, a sleeve is pre-stretched andmaintained in an expanded state by using a rigid core inserted therein.The cold-shrink sleeve shrinks to fit tightly over the cable insulationand the joint insulation upon physical removal of the rigid core. Again,while cold-shrink designs accomplish the desired objectives in thefield, currently available cold-shrink sleeves known in the art aredesigned to cold shrink along the entire length of the sleeve, which incurrent practice is generally greater than twelve inches, and theincreased dimension of the sleeve requires a removable core of equal orgreater length. As mentioned, components of such length prove difficultto assemble in the confined space common to joint assembly in a highvoltage environment and failure of the proper removal of the core mayresult in complete failure of the joint requiring reinstallation.Further, once installed, the joint is no longer disconnectable, since itis not possible to disassemble the joint without cutting off the sleeve.

Since the methods discussed herein have been employed in the art fordecades, numerous disclosures are known in the art that employ theinterference fit, heat-shrink characteristics, or cold-shrinkcharacteristics splicing apparatus and methods discussed above. Forexample, Fallot U.S. Pat. No. 3,980,374, entitled “Separable spliceconnector,” teaches of a separable splice connector for use with 15 to25 kilovolts and 600 amperes of current. The connector employs a unitarysplice body assembly. The splice body assembly is constructed of moldedelastic material and may be utilized for providing a straight splice.

A second apparatus comprising a pre-molded high voltage splice isdisclosed in Lien U.S. Pat. No. 5,041,027, entitled “Cable splice.” Liendiscloses a system for electrically connecting a first power cable endto a second power cable end. The splice system comprises a first probeadapted to be electrically connected to the first power cable end and asecond probe adapted to be electrically connected to the second powercable end and a cable splice. The cable splice further comprises twoends wherein a first female contact assembly is adapted to engage withthe first probe and a second female contact assembly is adapted toengage with the second probe thereby forming a splice.

In a further example, Yaworski U.S. Pat. No. 7,901,243, entitled“Methods and systems for forming a protected disconnectable jointassembly,” teaches of a method for forming a protected disconnectablejoint assembly using a disconnectable joint assembly wherein thedisconnectable coupling mechanism is selectively operable to disconnectthe cable connector from the busbar by severing the sleeve, but withoutsevering the secured cable. In short, Yaworksi discloses a cold-shrinksleeve with the cold-shrink portion being on the joint end. The methodfor assembling the joint assembly includes the use of “an electricaltransmission power cable including a conductor and a cable insulationlayer covering the conductor, the conductor having a terminal end; anelectrically conductive cable connector affixed to the terminal end ofthe power cable and having a connector coupling portion; a busbarincluding an electrically conductive busbar body, a busbar couplingportion extending from the busbar body, and a busbar insulation layercovering the busbar body; and a disconnectable coupling mechanismmechanically securing the cable coupling portion to the busbar couplingportion to provide a joint between the cable and the busbar.” TheYaworski method requires “maintaining the joint cover assembly in anexpanded state using a removable holdout device mounted within thesleeve body; mounting the joint cover assembly on the holdout over thejoint between the cable and the busbar; and thereafter removing theholdout device from the joint cover assembly to release the sleeve bodyto contract onto the disconnectable joint assembly such that the sleevebody circumferentially surrounds the joint between the cable and thebusbar, overlaps portions of the cable insulation layer and the busbarinsulation layer adjacent the joint, and applies a persistent radiallycompressive load on the cable insulation layer and the busbar insulationlayer.”

Numerous other splicing mechanisms employing the referenced apparatusand methods are known and utilized in the art. However, none of thecurrently employed systems provide for an effective splice utilizing acombination of cold-shrink and interference fit splice components.Current inefficient design tends to make the performance of this type ofsplicing unduly time-consuming, resulting in increased labor, time, andcost.

Thus, there exists a need for an invention which resolves thelimitations of the prior art by providing a suitable means forcompleting a field splice of common high voltage components employing acombination of cold-shrink and interference fit in a single splicecomponent. The single device of the present invention allows for the useof a shortened core at a first cold splice end and absence of a cableadapter at the interference fit second end.

While aforementioned methods and apparatuses are generally suitable forthe particular purpose discussed herein, it is clear that there exists aneed in the art for an improved method and apparatus that progresses thestate of the art, as well as one that provides the additional benefitsenumerated in the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the present invention and the objectivesother than those set forth above can be obtained by reference to thevarious implementations set forth in the illustrations of theaccompanying figures. Although the implementations illustrate certainaspects of the present invention, including the apparatus and method ofuse of the invention, the present invention, together with furtherobjectives and advantages thereof, may be more easily understood byreference to the drawings, examples, and the following description. Theexamples and figures are not intended to limit the scope of thisinvention, which is set forth with particularity in the claims asappended or as subsequently amended, but merely to clarify and exemplifythe invention. The detailed description makes reference to theaccompanying figures wherein:

FIG. 1 is a perspective view of the preferred embodiment of the presentinvention of the splice system; and

FIG. 2A, FIG. 2B, and FIG. 2C are perspective views depicting the methodfor installing the splice system, which includes a sleeve designed toutilize an interference fit at one end of the sleeve and a cold-shrinkfit at the alternate end of the sleeve in accordance with the preferredembodiment of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Provided herein is an improved unitary sleeve for splicing high voltagecomponents. This unitary sleeve includes a first end designed to accepta connector and removably attach thereto and a second end to cold shrinkover a cable inserted therein to provide improved assembly in the fieldand eliminate the need for excess components when servicing andestablishing high-voltage power systems.

A detailed description of the aforementioned embodiment of the presentinvention is disclosed herein. However, techniques of manufacture andresulting structures in accordance with the present invention may beembodied in a wide variety of forms and modes, some of which may bequite different from those in the disclosed embodiment. Consequently,the specific structural details disclosed herein are merelyrepresentative, yet in that regard, they are deemed to representsuitable implementations for purposes of disclosure and to provide abasis for the claims herein, which define the scope of the presentinvention. Well known methods, procedures, and substances for bothcarrying out the objectives of the present invention and illustratingthe preferred embodiment are incorporated herein but have not beendescribed in detail as not to unnecessarily obscure novel aspects of thepresent invention.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” As used herein, the terms “connected,”“coupled,” or any variant thereof mean any connection or coupling,either direct or indirect, between two or more elements; the coupling ofconnection between the elements can be physical, logical, or acombination thereof. Additionally, the words “herein,” “above,” “below,”and words of similar import, when used in this application, shall referto this application as a whole and not to any particular portions ofthis application. Where the context permits, words in the descriptionusing the singular or plural number may also include the plural orsingular number respectively. The word “or,” in reference to a list oftwo or more items, covers all of the following interpretations of theword: any of the items in the list, all of the items in the list, andany combination of the items in the list.

Turning to FIG. 1, shown is a perspective view of the preferredembodiment of sleeve 100 of the present invention utilized to splicecables in a high voltage system. Cable joints are designed to bedisconnected and reconnected without damaging the joint to allow forexpansion of the existing high voltage system, as well as service,maintenance, and testing of the high voltage system. Once a joint iscreated, continuity must be established to restore the connection. Oncea splice is created, exposure of the cables and/or the connectors to theelements may yield a fault point in the system. For example, if thesplice is not properly insulated from the elements, the intrusion ofwater in the splice may cause a fault in the system. Thus, it is commonin the art to include a snug-fitting sleeve to ensure isolation andprotection at the point of the splice.

Sleeve 100 is generally tubular and exhibits a substantially hollowcenter for insulting an electrical splice and carrying an electricalcurrent therethrough. Sleeve 100—including a first end 102 and a secondend 104—is primarily manufactured of one of two distinct materials,ethylene propylene diene monomers (EPDM) or silicones, common in theart. First end 102 is designed to act as a common cold-shrink connectionwell known in the art. In this instance, sleeve 100 is pre-stretched andmaintained in an expanded state by a rigid core 106 inserted therein.Once sleeve 100 is positioned over a cable, core 106 is physicallyremoved, or in some instances internally destroyed, and a portion ofsleeve 100 shrinks to fit tightly over the cable insulation and thejoint insulation. It is contemplated by the present disclosure that anyknown cold-shrink method and corresponding apparatuses (i.e., generallyrubber elastomers with high performance physical properties that havebeen factory expanded or pre-stretched and assembled onto a supportingand removable rigid core typically manufactured of a high-strengthplastic) may be utilized in accordance with the present invention,including but not limited to the use of split core, pop core, break-awaycore, unwind core, and the like known and utilized in the art as well assimilar cores developed in the future which achieve the desiredobjectives of known cold-shrink components.

Second end 104 of sleeve 100 is designed to accept a component andsecure to said connector. In this connection, second end 104 of sleeve100 is designed to removably or permanently (depending on the desiredconnector) connect securely by means of an interference fit. In thepresent embodiment, the inside diameter of the second end 104 of sleeve100 is smaller than the inner diameter of the component to which it isto be secured. This interference fit allows for a continuous shieldcovering and provides for a leak-proof submersible design between thecable(s) and connector(s) at the joint. Further, a groove 108 is locatedadjacent to second end 104 of sleeve 100. Groove 108 encompasses thecircumference of sleeve 100 and provides a location for a restraint,such as a hose clamp, to further secure the component to sleeve 100.

Turning to the next set of figures, FIGS. 2A, 2B, and 2C are perspectiveviews of the method for installing the splice system 200 of thepreferred embodiment of the present invention depicted in a series ofsteps and related figures. In the present method, an open joint iscreated and exposed cable 204 is prepared. In a typical cableinstallation, insulation is stripped back from the cable end of thetermination preparation. The insulation shield is also pulled back awayfrom the cable end. Further, the outer cable jacket is stripped backbeyond the insulation shield. In addition, the insulation is chamferedto reduce assembly forces resulting from the insertion of cablepreparation into a premolded expandable product (i.e., sleeve 202). Asshown in FIG. 2A, prepared cable 204 is inserted into first end 206 ofsleeve 202 and further within rigid core 208 removably fixedtherewithin, effectively expanding cold-shrink first end 206 of sleeve202. Cold-shrink first end 206 of sleeve 202 is in an expanded state toallow for a lineman to position cable 204 within first end 206 of sleeve202 without requiring substantial force imparted by a lineman performingthe splice. At second end 210 of sleeve 202, inside diameter of secondend 210 of sleeve 202 is designed smaller than the outside diameter of aprobe of common component 212. While one of ordinary skill in the artwill readily recognize, component 212 may be any known splice componentcommonly used in the art such as disconnectable I-bus, Y-bus, or H-busjoint component. The respective diameters of component 212 and secondend 210 of sleeve 202 allows for an interference fit once sleeve 202 isforced over probe of component 212 as shown in FIG. 2B. Thisinterference fit generates a continuous insulation covering and providesfor a leak-proof submersible design between the cables and components atthe joint. To complete the splice, rigid core 208 is manually removed bythe lineman at the point of the splice by withdrawing rigid core 208from first end 206 of sleeve 202. Upon removal of rigid core 208, firstend 206 of sleeve 202 shrinks to fit tightly over the cable insulationthereby forming a resistant and snug splice at cable portion of joint asthe memory action of the specially formulated material ensures apermanent, durable environmental seal and insulation.

While certain aspects of the device are presented below in certain claimforms, the inventor contemplates the various aspects of the apparatusand method in any number of claim forms. Accordingly, the inventorreserves the right to add additional claims after filing the applicationto pursue such additional claim forms for other aspects of the apparatusand method.

Thus, there has been summarized and outlined, generally in broad form, aplurality of the most important features of the present invention. Whilethis summary is presented so that the novelty of the presentcontribution to the related art may be better appreciated, it willfurther be apparent that additional features of the invention describedhereinafter (which will form the subject matter of the claims appendedhereto) will further define the scope, novelty, and in certain instancesthe improvements upon any existing art. The following descriptionprovides specific details for a thorough understanding of, and enablingdescription for, various examples of the improvement in the describedfield of art. One skilled in the art will understand that the method andapparatus may be practiced without many of these details, and it is tobe readily understood that the invention presented herein is not limitedin its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the various figures integrated and categorized herein.For example, in some instances, well-known structures and functions havenot been shown or described in detail to avoid unnecessarily obscuringthe description of the examples of the invention. It is intended thatthe terminology used in the description presented below be interpretedin its broadest reasonable manner, even though it is being used inconjunction with a detailed description of certain examples of theinvention. Although certain terms may be emphasized, any terminologyintended to be interpreted in any restricted manner will be overtly andspecifically defined as such in this detailed description section. Thoseskilled in the art will appreciate that the disclosure of the presentinvention may readily be utilized as a basis for the designing of othersimilar structures, methods, and systems for carrying out the variouspurposes and objectives of the present invention.

We claim:
 1. A joint assembly comprising: a sleeve having a first endand a second end for insulating an electrical splice; a core disposedwithin said first end; wherein said second end is designed to mate witha bus and secure to said connector; and wherein said core is removablyattached so that upon removal of said core said first end shrinks tosecure around a cable inserted therein.
 2. The joint assembly of claim1, wherein the sleeve is manufactured of EPDM.
 3. The joint assembly ofclaim 1, wherein the core is a spiral ribbon core.
 4. The joint assemblyof claim 1, wherein the core is a solid pullout core.
 5. The jointassembly of claim 4, wherein the solid pullout core is comprised of asupport core removably insertable in the end section for holding the endsection in a stretched configuration and a film layer inserted between acorresponding one of the support cores and a corresponding one of theend sections.
 6. The joint assembly of claim 5 wherein the film layer isto be folded back on itself to form an inner film layer adjacent to thecorresponding one of the support cores and to form an outer film layeradjacent to the corresponding one of the end sections.
 7. The jointassembly of claim 1, wherein the sleeve comprises a circumferentialgroove positioned adjacent to the second end.
 8. A joint assemblycomprising: a sleeve manufactured of EPDM having a first end and asecond end for insulating an electrical splice; a core disposed withinsaid first end; wherein said second end is designed to mate with a busand secure to said connector; and wherein said core is removablyattached so that upon removal of said core said first end shrinks tosecure around a cable inserted therein.
 9. The joint assembly of claim8, wherein the core is a spiral ribbon core.
 10. The joint assembly ofclaim 8, wherein the core is a solid pullout core.
 11. The jointassembly of claim 10 wherein the solid pullout core is comprised of asupport core removably insertable in the end section for holding the endsection in a stretched configuration and a film layer inserted between acorresponding one of the support cores and a corresponding one of theend sections.
 12. The joint assembly of claim 11 wherein the film layeris to be folded back on itself to form an inner film layer adjacent tothe corresponding one of the support cores and to form an outer filmlayer adjacent to the corresponding one of the end sections.
 13. Thejoint assembly of claim 8, wherein the sleeve comprises acircumferential groove positioned adjacent to the second end.
 14. Amethod for providing a high voltage joint assembly including: a preparedelectrical transmission power cable including a conductor and a cableinsulation layer covering the conductor, wherein the conductor includesa terminal end; an electrically conductive cable connector affixed tothe terminal end of the power cable and having a connector couplingportion; a sleeve having a first end and a second end for insulating anelectrical splice and carrying an electrical current there through; acore disposed at said first end; a busbar including an electricallyconductive busbar body, a busbar coupling portion extending from thebusbar body, and a busbar insulation layer covering the busbar body;wherein said second end of sleeve is designed to mate with a bus andsecure to said connector and wherein said core is removably attached sothat upon removal of said core said second end shrinks to secure arounda cable inserted therein; maintaining the joint cover assembly in anexpanded state; and releasing the sleeve body by removing said core tocontract onto the joint assembly such that the sleeve bodycircumferentially surrounds the joint between the cable and the busbar,overlaps portions of the cable insulation layer and the busbarinsulation layer adjacent the joint, and applies a persistent radiallycompressive load on the cable insulation layer and the busbar insulationlayer.
 15. The method of claim 14, wherein the sleeve is manufactured ofEPDM.
 16. The method of claim 14, wherein the core is a spiral ribboncore.
 17. The method of claim 14, wherein the core is a solid pulloutcore.
 18. The method of claim 17, wherein the solid pullout core iscomprised of a support core removably insertable in the end section forholding the end section in a stretched configuration and a film layerinserted between a corresponding one of the support cores and acorresponding one of the end sections.
 19. The method of claim 18,wherein the film layer is to be folded back on itself to form an innerfilm layer adjacent to the corresponding one of the support cores and toform an outer film layer adjacent to the corresponding one of the endsections.
 20. The method of claim 14, wherein the sleeve comprises acircumferential groove positioned adjacent to the second end.